It liquefies when heated under pressure, and its melting point lies between 446° C. and 457° C. The vapour of arsenic is of a golden yellow colour, and has a garlic odour.
It liquefies at -40° C. and becomes solid at -118.9° C. (K.
It is a colourless gas 42 times heavier than air, and liquefies at 15° under 40 atmospheres, solidifying when the pressure is diminished.
It is a colourless fuming gas, which liquefies under ordinary pressure at -50°, and under a pressure of 15 atmospheres at 16°; it may be solidified to a snow-like mass.
On the other hand, if a gas be sufficiently cooled and compressed, it liquefies; this transition is treated theoretically in the article Condensation Of Gases, and experimentally in the article Liquid Gases.